The present teachings are predicated upon providing an improved disc brake system for use with vehicles. For example, the disc brake system may be used with almost any vehicle (e.g. car, truck, bus, train, airplane, or the like). Alternatively, the disc brake system may be integrated into assemblies used for manufacturing or other equipment that require a brake such as a lathe, winder for paper products or cloth, amusement park rides, or the like. However, the present teachings are most suitable for use with a passenger vehicle (i.e. a car, truck, sports utility vehicle, or the like).
Generally, a braking system includes a rotor, a caliper body, a support bracket, an inboard brake pad, and an outboard brake pad that are on opposing sides of the rotor. The caliper body further includes one or more fingers, a piston bore, and a bridge that connects the one or more fingers to the piston bore. The piston bore houses a piston. The piston bore has a bore axis that the piston moves along during a brake apply and a brake retract. The piston bore may include a fluid inlet, a closed wall, a front opening, and a cylindrical side wall that includes a seal groove located near the front opening. Typically, the fluid inlet is located in the closed wait of the piston bore so that when pressure is applied the fluid will flow into the piston bore. During a pressure apply the fluid will push the piston towards the front opening and into contact with a brake pad. Generally, brake pads include a pressure plate and friction material. During each pressure apply the friction material contacts a rotor, which removes a small portion of the friction material. Over repeated pressure applies the friction material slowly reduces, and due to the location of the brake pads it may be difficult for a user to cheek the thickness of the friction material, users may not check brake pad thickness, or a user may forget to check brake pad thickness. If the friction material is reduced beyond a certain point, braking performance may begin to reduce. What is needed is a wear indicator that monitors the thickness of the friction material and when the friction material thickness reaches a predetermined thickness, the wear indicator makes an audible noise so that the user is alerted to check the thickness of the friction material before braking performance is impacted.
Examples of clip on wear indicators are disclosed in U.S. Pat. Nos. 3,611,283; 4,037,089; 4,124,105; 4,241,327; 4,460,067; 4,498,559; 4,742,326; 5,388,670; 6,311,554 all of which are expressly incorporated herein by reference for all purposes. Examples of electronic wear indicators are disclosed in U.S. Pat. Nos. 3,297,985; 3,882,448; and 6,302,241 all of which are incorporated herein by reference for all purposes.
What is needed is a wear indicator that attaches to the pressure plate of a brake pad and is fastened to the pressure plate in a manner so that the wear indicator is not damaged and/or inadvertently removed during installation of one or more parts onto the brake pad and/or the brake pad being installed into the brake system. What is needed is a wear indicator that produces an audible sound so that a user is adequately alerted when a frictional material thickness reaches a predetermined thickness.